This invention relates to an adaptive quantization apparatus in a predictive encoding system or a data compression system for a signal representing a moving image.
In transmission of data representing a moving image, it is desirable to compress the image data or to reduce the number of bits representing the image data without appreciably lowering the quality of the transmitted image. Quantizing image data enables compression of the image data. Predictive encoding of image data also enables compression of image data.
As will be described later, prior art image-signal encoding apparatus have some problems.